When you back a Kickstarter project, you are not making a donation or a gift.
Well, not necessarily. If you don't ask for a reward, or you select a reward level that says something like, "Thanks for your donation," yeah, it's a gift or a donation. But if you select a reward that says you will receive something, you have entered a contract with the project creator and they owe you what they promised (or at least a refund).
Kickstarter has made this clear since at least October 2012 and through today:
By creating a fundraising campaign on Kickstarter, you as the Project Creator are offering the public the opportunity to enter into a contract with you. By backing a fundraising campaign on Kickstarter, you as the Backer accept that offer and the contract between Backer and Project Creator is formed. ...
By backing or creating a fundraising campaign on Kickstarter, you agree to be bound by this entire Agreement, including the following terms:
...
- Project Creators are required to fulfill all rewards of their successful fundraising campaigns or refund any Backer whose reward they do not or cannot fulfill.
Now, if a Kickstarter goes bad, you might never get your money back. If the project is just mismanaged or erroneously hopeful, where are you going to get your refund from? A large project is likely behind a corporation, an entity whose primary purpose is to shield the owners from liability. If everything goes bad, the company will declare bankruptcy and you'll receive somewhere between little and nothing. For a smaller project, is it really cost effective to file a lawsuit, especially if the creator is in a another state or country? If the creator bankrupted themselves in the process, there may be nothing to gain.
Backing something on Kickstarter is essentially pre-ordering a product from a company with an unusually high risk of going bankrupt. You may never get what you were promised, but it is essentially a purchase and you have a right, at least in principle, to the product or a refund.